Code
B2815
HUMMER
B — Body
Keyless Entry Receiver Signal Loss
Views:
UK: 15
EN: 19
RU: 18
AI status
Completed
Completed
100%
Causes
- Dead or weak key fob battery
- Faulty keyless entry receiver/module or antenna
- Poor or corroded wiring or connector to receiver
- Blown fuse or power supply issue to receiver
- Loss of communication between receiver and Body/BCM (CAN, LIN, Class 2)
- Radio frequency (RF) interference or improper frequency
Symptoms
- Keyless entry/unlock/lock functions do not respond to remote
- Intermittent operation of remote locking/unlocking
- Vehicle may not recognize key for passive entry or push-button start
- No dash or door module response when pressing fob buttons
- Possible security/anti-theft warnings or immobilizer behavior
What to check
- Verify key fob operation by replacing battery or testing with spare fob
- Check for other stored related DTCs with a scan tool
- Inspect fuses and power supply to the receiver/module
- Visually inspect receiver antenna and connectors for corrosion or damage
- Check vehicle battery voltage and ground connections
- Confirm receiver/module is powered and has proper ground
Signal parameters
- Receiver module supply voltage: battery nominal ~11–14 V with ignition states as required
- Expected RF carrier frequency: typically ~315 MHz (North America) or ~433.92 MHz (other regions) depending on market
- When fob button pressed: receiver should detect RF carrier and produce a valid data frame to BCM/BCM bus
- CAN/LIN/Class 2 messages: receiver should transmit status or keyless events when RF detected
- Typical RF receive sensitivity: receiver should detect fob at normal range; severe attenuation indicates antenna/wiring issue
Diagnostic algorithm
- Verify symptom: attempt lock/unlock with known-good spare key fob and from various distances.
- Replace key fob battery and retest. If spare fob works, issue likely fob-related.
- Use scan tool: read and record DTCs, data list for keyless module/receiver, and available live data when pressing fob buttons.
- Inspect fuses and relays for the receiver circuit; verify receiver has battery feed and proper ground at its connector.
- Visually inspect antenna, coax (if present), and receiver/module wiring for damage, corrosion, or loose connections; repair as needed.
- Probe power and ground at the receiver module with multimeter; verify nominal voltage and continuity to chassis ground.
- With an RF detector or oscilloscope (if available) check for RF carrier at the antenna/receiver when a button on fob is pressed.
- Check communication between receiver and BCM (CAN/LIN/Class 2): verify messages or use module communication tests on scan tool.
- Reflash or reprogram receiver/module or re-learn key fobs per manufacturer procedures if configuration or coding is suspected.
- If receiver wiring, power, and fobs test good and communication still fails, replace receiver/module and verify system operation.
- After repair, clear codes and retest all keyless functions and confirm no reoccurrence.
Likely causes
- Weak or dead key fob battery
- Receiver antenna disconnected, damaged, or corroded
- Fuse for receiver circuit blown or receiver has no battery feed
- Loose or damaged connector/wiring to receiver or BCM
- Receiver module failure
- Key fob has lost programming or is defective
Fault status
Status
Keyless entry receiver signal loss — receiver did not detect remote transmitter signals or did not report keyless events to vehicle network.
Repair difficulty: Medium
Diagnostic time: 0.5 - 2.0 hours
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Repair manuals
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69
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